1. Field of the Invention
This invention relates to a drawing machine carriage comprising a carriage which is horizontally movable on a horizontal guide rail and a vertical guide rail with a vertically movable carriage. The carriage supports a drawing head and a brake for the horizontal carriage such that the brake is activated by an operational element mounted on the vertical carriage by means of a transmission.
2. Description of the Prior Art
One such drawing machine carriage which is shown in German Patent No. 25 07 446 utilizes a cable pulley as the transmission, whereby the cable operates over casters on the braking lever and on the underside of the vertical guide rail, and the end of the cable is secured to the operational lever. In the first position of the operational lever, the cable tension is provided with a predetermined first tension against the load spring of the brake lever, which is in the neutral position. In a second position of the operational lever, the cable is more firmly stretched over a dead center and in response to the greater cable tension, the brake lever is shifted into the braking position. The disadvantage of this braking mechanism is in particular that the transmission and the operational lever are under a relatively large force load in both the neutral position and the braking position. This causes a relatively constant stress on the linking casters by the cable tension, which results in labored operation of the operational element, since the operational element can be first moved to either the braking position or the neutral position when the requisite force has been overcome. The user must exercise relatively large torque on the operational lever in order to release the brake. Thus, the vertical carriage moves in a halting manner which is undesirable.